Contemporary lighting techniques for aesthetic lighting or safety illumination applications commonly rely upon lateral leakage of light flux from one or more optical fibers that are optically coupled to a source of light for distributing the light from the surface of the optical fiber or fibers over the length thereof. This produces a pleasing effect of light in any color being distributed in a narrow strip over a substantial distance from the illuminating light source. Glass optical fibers or plastic optical fibers having selected lateral emission properties may be used in such lighting applications that promote flexibility and immunity from electrical shock and that exhibit low-cost, superior characteristics over traditional neon tubes or discrete light sources oriented in a linear array.
Optical fibers for use in such lighting applications commonly include light-scattering schemes within the fibers to enhance lateral emission of light from the fibers, which schemes may include material anomalies such as particles or bubbles distributed in the core material of the fibers to deflect light flux from within tile core material through the surface of the fibers substantially uniformly over the length of the fibers. Schemes of this type tend to exhibit higher levels of light flux laterally emitted from the optical cable closest to the light source or sources disposed near one end or both ends of the fibers, and lower levels of light flux laterally emitted from the fibers a locations remote from the light source. Techniques for graduating the density of light scattering anomalies per unit length of fiber in order to compensate for the non-uniformity of the illumination with distance along the fibers have not been successful for low-cost production of optical fibers of substantial length.